The absence of palliation and curative therapy for various end-stage chronic pulmonary diseases emphasizes the therapeutic potential of clinical lung transplantation. Success in this venture will require standardization in an experimental animal model of techniques such as determination of histocompatibility, detection of early rejection, use of immunosuppressant therapy, and characteristics of lung allograft rejection. Because of similarities of the lower primates to the human, the baboon would represent a unique model for these studies. The objectives of the proposed research are: 1. To determine the effect of horse antiglobulin to baboon lymphocytes (ALG) upon the recipient's immunologic response pre-and postoperatively. 2. To evaluate the effect of ALG alone on the survival of lung allografts and in common with other immunosuppressives. 3. To evaluate the functional capacity of the primate lung allograft and factors influencing impaired function. 4. To delineate the characteristics of various rejection stages of primate lung allograft rejection by light microscopic, immunofluorescent, and ultrastructural studies. 5. To evaluate mixed lymphocyte culture and cell mediated lympholysis in matching baboon donor and recipient in lung allotransplantation. 6. To detect early lung rejection using leukocyte migration inhibition and reactive lymphocyte blastogenesis. 7. To evaluate the passive administration of an F(ab')2 fragment of baboon lymphocytotoxic antibody plus injection of donor bone marrow cells in survival of lung allografts.